The parents of first lady Melania Trump have become legal permanent residents of the United States and are close to obtaining their citizenship, according to people familiar with their status, but their attorney declined to say how or when the couple gained their green cards.

Immigration experts said Viktor and Amalija Knavs very likely relied on a family reunification process that President Trump has derided as “chain migration” and proposed ending in such cases.

The Knavses, formerly of Slovenia, are living in the country on green cards, according to Michael Wildes, a New York-based immigration lawyer who represents the first lady and her family.

“I can confirm that Mrs. Trump’s parents are both lawfully admitted to the United States as permanent residents,” he said. “The family, as they are not part of the administration, has asked that their privacy be respected, so I will not comment further on this matter.”

The Knavses are awaiting scheduling for their naturalization oath ceremony, according to a person with knowledge of their immigration filings. Permanent residents typically have to hold green cards for five years before they can apply for U.S. citizenship.

It is unclear when the Knavses first moved to the United States, but by late 2007, Viktor Knavs was listed in public records as residing at Mar-a-Lago, Trump’s private club in Palm Beach, Fla.

Questions over the Knavses’ immigration status have escalated since Trump campaigned for the White House on a hard-line anti-immigration agenda. Those questions grew sharper last month, when the president proposed ending the decades-long ability of U.S. citizens to sponsor their parents and siblings for legal residency in the United States.

Trump has repeatedly blasted the long-standing policy as “chain migration.” In last month’s State of the Union address, the president called that process a threat to Americans’ security and quality of life. Under his plan, he said, only spouses and minor children could be sponsored for legal residency.

But immigration experts said that such a path was the most likely method his in-laws would have used to obtain permits to live in the United States.

Matthew Kolken, a partner at a New York immigration law firm, said there are only two substantive ways Trump’s in-laws could gain green cards: through sponsorship by their daughter or an employer. The latter is unlikely, he said, as it would require evidence that there were no Americans who could do the job for which they were hired.

The Knavses are reportedly retired. In Slovenia, Viktor Knavs, now 73, worked as a chauffeur and car salesman. Amalija Knavs, now 71, was a pattern maker at a textile factory.

David Leopold, an immigration lawyer and a past president of the American Immigration Lawyers Association, said the first lady’s sponsorship of her parents appears to be the only reasonable way they would have obtained green cards because the process currently gives preferential treatment to parents of U.S. citizens.

“That would be the logical way to do it, the preferred way to do it and possibly the only way to do it under the facts that I know,” Leopold said.

Foreigners can also petition for refugee status or other humanitarian programs, according to the Department of Homeland Security.

A White House spokesman and a spokeswoman for the first lady declined to comment.

The revelation that the Knavses have permanent legal residency threw a spotlight once again on questions about Melania Trump’s immigration history.

Wildes, her attorney, has said that she first came to the United States from Slovenia in 1996 for modeling work, first on a visitor’s visa and then a work permit. In 2000, he said, Trump sponsored herself for a green card based on her “extraordinary ability” as a model.

However, the Associated Press reported in 2016 that Trump was paid for 10 modeling jobs in 1996 before she received legal authorization to work in the United States.

She has not provided details about how she proved to the U.S. government that she qualified to receive a green card for her “extraordinary ability,” a category generally reserved for highly accomplished people such as ­Nobel Prize winners.

In 2001, several years after meeting Donald Trump, she received a green card that granted her permanent residency, Wildes has said. She became a U.S. citizen in 2006, the year after she and Trump were married.

“I came here for my career,” Melania Trump told Harper’s ­Bazaar in January 2016. “I did so well. I moved here. It never crossed my mind to stay here without papers. That is just the person you are. You follow the rules. You follow the law.”

After their daughter moved to the United States, the Knavses joined her, living on and off with the Trumps. As of December 2007, Viktor Knavs was using Mar-a-Lago as his address and had a Florida-based Mercedes-Benz registered in his name, according to public records.

They are not the only family members to join Melania Trump from Slovenia: Her older sister, Ines, lives in an apartment in a Trump-owned building on Park Avenue in New York, public records show.

Since the first lady and her son, Barron, moved into the White House last summer, her parents have been seen frequently in Washington.

Several years ago, their attorneys contacted the office of Sen. Charles E. Schumer (D-N.Y.), now the Democratic minority leader, for help checking on the status of their petition for a green card with U.S. Citizenship and Immigration Services, according to a person familiar with the outreach.

Such efforts are not unusual, and some congressional staffs, including Schumer’s, have a dedicated immigration case worker to handle such requests. Schumer’s office declined to comment.

In his State of the Union address on Jan. 30, President Trump offered a four-point immigration plan that he said “protects the nuclear family by ending chain migration.”

“Under the current broken system, a single immigrant can bring in virtually unlimited numbers of distant relatives,” he said in his speech. “Under our plan, we focus on the immediate family by limiting sponsorships to spouses and minor children. This vital reform is necessary, not just for our economy, but for our security and our future.”

Trump underscored his position in a Feb. 6 tweet.

“We need a 21st Century ­MERIT-BASED immigration system,” he tweeted. “Chain migration and the visa lottery are outdated programs that hurt our economic and national security.”

Democrats and some Republicans have opposed that measure. Last week, the Senate defeated legislation offered by Sen. Charles E. Grassley (R-Iowa) and backed by the White House that included Trump’s proposal.